A so-called tandem color laser printer includes a plurality of photosensitive drums which correspond to respective colors, e.g., yellow, magenta, cyan, and black, and which are arranged in tandem side by side in a horizontal direction.
The tandem color laser printer includes a transfer unit disposed opposing the photosensitive drums and configured to transfer toner images formed on the photosensitive drums to a sheet during a conveyance of the sheet.
For example, the transfer unit is provided with a housing formed of metal plate that is disposed within a conveyor belt extending between a drive roller and a driven roller, and the housing holds transfer rollers opposing respective photosensitive drums.